Computer System and Method Which Boots from a Bootup-Memory-Image Stored in Nonvolatile Memory and Copies Data Within an Address Range of Predetermined Width to Main Memory So That the System Boots Quickly After Initialization

1. A computer system which boots said system from a bootup-memory-image, after initialization procession of an operating system (OS) and application programs, stored in a nonvolatile memory unit forming part of a main memory device, when first write access occurs after system operations, copies data from a block of the bootup-memory-image after intialization processing of an OS and application programs to a readable/writable main memory unit forming another part of the main memory device for each block of the bootup-memory-image, performs write operation on the copy of the block of the bootup-memory-image, and subsequently switches access to a block of the bootup-memory-image to which data has already been copied to access the copy.

2. A computer system comprising: a main memory device which comprises a nonvolatile memory unit which stores a bootup-memory-image, after initialization processing of an operating system (OS) and application program, and a readable/writable main memory unit; and a data processing apparatus which boots said system from the bootup-memory-image stored in the nonvolatile memory unit, and every time write access occurs from the OS or application program to the nonvolatile memory unit during system operation, copies data within an address range with a predetermined width which includes an address at which write access has occurred from the nonvolatile memory unit to an alternative area ensured in the main memory unit, and performs setting to translate subsequent access to the address range with the predetermined width into access to the alternative area.

3. A system according to claim 2 , wherein said data processing apparatus reads out data from the nonvolatile memory unit when read access to the nonvolatile memory unit occurs from the OS or application program during system operation.

4. A computer system comprising: a main memory device which comprises a nonvolatile memory unit which stores a bootup-memory-image, after intialization processing of an operating system (OS) and application program, and a readable/writable main memory unit; a data processing apparatus which boots said system from the bootup-memory-image stored in the nonvolatile memory unit, and every time write access occurs from the OS or application program to the nonvolatile memory unit during system operation, copies data within an address range with a predetermined width which includes an address at which write access has occurred from the nonvolatile memory unit to an alternative area ensured in the main memory unit, and performs setting to translate subsequent access to the address range with the predetermined width into acess to the alternative area, wherein said data processing apparatus reads out data from the nonvolatile memory unit when read access to the nonvolatile memory unit occurs from the OS or application program during system operation; and a protection information unit which stores a protection attribute for each address range having a predetermined width and including addresses to be designated when the OS and the application program access said main memory device, wherein said data processing apparatus refers to said protection information unit for a protection attribute of the address range having the predetermined width and including an address at which the write access has occurred, performs the copy operation and the setting only when the protection attribute is readable/writable, and determines an error when the protection attribute is read only.

5. A system according to claim 4 , further comprising other nonvolatile memory units which store a main storage bootup-memory-image different from the main storage bootup-memory-image stored in the nonvolatile memory unit, and a selecting unit which selects the nonvolatile memory unit and any one of said other nonvolatile memory units at the time of bootup.

6. A system according to claim 4 , further comprising not less than one additional nonvolatile memory unit which stores a corrected image of a portion of the main storage bootup-memory-image stored in the nonvolatile memory unit, and re-mapping means for remapping a physical address mapped to an area corresponding to the corrected image of the bootup-memory-image which is stored in said additional nonvolatile memory unit to a physical address mapped to the corrected image in said additional nonvolatile memory unit.

7. A system according to claim 4 , wherein the nonvolatile memory unit comprises a read only storage device.

8. A system according to claim 4 , wherein the nonvolatile memory unit comprises a readable/writable storage device.

9. A computer system comprising: a main memory device which comprises at least one nonvolatile memory unit which stores a bootup-memory-image, after initialization processing of an operating system (OS), and an application program, and a readable/writable main memory unit; and a data processing apparatus which boots said system from the main storage bootup-memory-image stored in the nonvolatile memory unit, said data processing apparatus comprising access processing means for, when write access occurs from the OS or the application program to said main memory device during system operation, if there is no violation against a protection mode set in a mapping table in which mapping information of physical block addresses of the nonvolatile memory unit and a read only pseudo-protection mode are initially set to logical block addresses of said system, accessing the main memory unit of said main memory device upon translating a logical address into a physical address in accordance with mapping information set in the mapping table, and if there is a violation against the protection mode, copying data in a block including an address at which write access has occurred from the nonvolatile memory unit to an alternative area ensured in the main memory unit only when a readable/writable attribute is determined upon referring to a protection information unit holding an intrinsic protection attribute of an access destination logical block, and processing the write access again upon updating the mapping table such that a block address of the alternative area is mapped to the access destination logical block and a protection mode coincides with the intrinsic protection attribute.

10. A system according to claim 9 , wherein said data processing apparatus comprises mapping table initialization means for creating at the time of system bootup a mapping table in which mapping information of physical block addresses of the nonvolatile memory unit and a read only pseudo protection mode are set for logical block addresses of said system.

11. A computer system comprising: a main memory device which comprises a nonvolatile memory unit which stores a main storage bootup-memory-image, after initialization processing of an operating system (OS) and an application program, and a readable/writable main memory unit; and a data processing apparatus which boots said system from the main storage bootup-memory-image stored in the nonvolatile memory unit, said data processing apparatus comprising status table initialization means for creating at the time of system bootup a status table in which a status indicating copy incomplete is set for each physical block address of the nonvolatile memory unit, and a memory access unit which, when write access occurs from the OS or the application program to the nonvolatile memory unit during system operation and a status set in the status table indicates copy incomplete, copies data in a write destination physical block from the nonvolatile memory unit to an alternative block reserved in advance in the main memory unit only when a readable/writable attribute is determined upon referring to a protection information unit holding an intrinsic protection attribute of an access destination physical block, accesses the alterative block with a physical address obtained by changing a block address of a physical address for the write access into a block address of the alternative block upon updating a status in the mapping table to indicate that copying of the access destination physical block is complete, and when write access occurs from the OS or the application program to the nonvolatile memory unit during system operation and a status set in the status table indicates copy complete, accesses the alternative block with a physical address obtained by changing a block address of a physical address for the write access into a block address of the alternative block.

12. A system according to claim 10 , wherein said main memory device comprises a plurality of nonvolatile memory units including the nonvolatile memory unit, which store different main storage bootup-memory-images of after initialization processing of the OS and the application program, said data processing apparatus comprises selection means for selecting one of the plurality of nonvolatile memory units at the time of system bootup, and the mapping table initialization means creates at the time of system bootup a mapping table in which mapping information of physical block addresses of the selected nonvolatile memory unit and a read only pseudo protection mode for logical block addresses of said system are set.

13. A system according to claim 10 , wherein the mapping table initialization means re maps at the time of system bootup a physical block address mapped to an area corresponding to a corrected image of the main storage bootup-memory-image which is stored in the additional nonvolatile memory unit to a physical address mapped to the corrected image in the additional nonvolatile memory unit.

14. A computer system startbootup method comprising the steps of: booting the system from a main storage bootup-memory-image, after intialization processing of an operating system (OS) and an application program, which is stored in a nonvolatile memory unit forming part of a main memory device; when first write access occurs after system operation, copying, for each area of the main storage bootup-memory-image after intialization processing of an OS and application programs which has a predetermined width, data of the area to a readable/writable main memory unit forming another part of the main memory device and performing write operation on the copy of the block of the bootup-memory-image; and subsequently switching access to an area of the main storage bootup-memory-image to which data has already been copied to access the copy.

15. A computer system bootup method for a computer system comprising the steps of: booting the system from a main storage bootup-memory-image, after initialization processing of an operating system (OS) and an application program, which is stored in a nonvolatile memory unit of a main memory device which comprises the nonvolatile memory unit which stores the bootup-memory-image and a readable/writable main memory unit; and every time write access occurs from the OS or application program to the nonvolatile memory unit during system operation, copying, from the nonvolatile memory unit to an alternative area ensured in the main memory unit, data within an address range with a predetermined width which includes an address at which write access has occurred, and performing setting to translate subsequent access to the address range with the predetermined width into access to the alternative area.

16. A method according to claim 15 , further comprising the step of reading out data from the nonvolatile memory unit when read access to the nonvolatile memory unit occurs from the OS or application program during system operation.

17. A computer system bootup method comprising the steps of: booting the system from a main storage bootup-memory-image, after intialization processing of an operating system (OS) and an application program, wich is stored in a nonvolatile memory unit of a main memory device which comprises the nonvolatile memory unit which stores the bootup-memory-image and a readable/writable main memory unit; every time write access occurs from the OS or application program to the nonvolatile memory unit during system operation, copying, from the nonvolatile memory unit to an alternative area ensured in the main memory unit, data within an address at which write access has occurred, and performing setting to translate subsequent access to the address range with the predetermined width into access to the alternative area; reading out data from the nonvolatile memory unit when read access to the nonvolatile memory unit occurs from the OS or application program during system operation; referring to a protection attribute of an address range having a predetermined width and including an address at which the write access has occurred from a protection information unit which stores a protection attribute for each address range having the predetermined width and including addresses to be designated when the OS and the application program access the main memory device, and performing the copy operation and the setting only when the protection attribute is readable/writable, and determining an error when the protection attribute is read only.

18. A method according to claim 17 , wherein other nonvolatile memory units which store a main storage bootup-memory-image different from the main storage bootup-memory-image stored in the nonvolatile memory unit is provided, and the step of booting comprises the step of selecting the nonvolatile memory unit and any one of the other nonvolatile memory units at the time of bootup.

19. A method according to claim 17 , wherein not less than one additional nonvolatile memory unit which stores a corrected image of a portion of the bootup-memory-image stored in the nonvolatile memory unit is provided, and the method further comprises the step of re-mapping a physical address mapped to an area corresponding to the corrected image of the bootup-memory-image which is stored in the additional nonvolatile memory unit to a physical address mapped to the corrected image in the additional nonvolatile memory unit.

20. A recording medium storing a bootup program for a computer system which comprises a main memory device which comprises at least one nonvolatile memory unit which stores a bootup-memory-image after, initialization processing of an operating system (OS) and an application program, and a readable/writable main memory unit; and a data processing apparatus which boots the system from the bootup-memory-image stored in the nonvolatile memory unit, the bootup program comprising a program, in the data processing apparatus, which implements an access processing sequence of, when write access occurs from the OS or the application program to the main memory device during system operation, if there is no violation against a protection mode set in a mapping table in which mapping information of physical block addresses of the nonvolatile memory unit and a read only pseudo protection mode are initially set to logical block addresses of the system, accessing the main memory unit of the main memory device upon translating a logical address into a physical address in accordance with mapping information set in the mapping table, and if there is a violation against the protection mode, copying data in a block including an address at which write access has occurred from the nonvolatile memory unit to an alternative area ensured in the main memory unit only when a readable/writable attribute is determined upon referring to a protection information unit holding an intrinsic protection attribute of an access destination logical block, and processing the write access again upon updating the mapping table such that a block address of the alternative area is mapped to the access destination logical block and a protection mode coincides with the intrinsic protection attribute.

21. A medium according to claim 20 , wherein the bootup program comprises a program, in the data processing apparatus, which implements a mapping table initialization sequence of creating at the time of system bootup a mapping table in which mapping information of physical block addresses of the nonvolatile memory unit and a read only pseudo protection mode are set for logical block addresses of the system.

22. A recording medium storing a startbootup program for a computer system including a main memory device which comprises a nonvolatile memory unit which stores a bootup-memory-image after initialization processing of an operating system (OS) and an application program, and a readable/writable main memory unit, and a data processing apparatus which boots the system from the bootup-memory-image stored in the nonvolatile memory unit, the bootup program comprising a program, in the data processing apparatus, which implements a status table initialization sequence of creating at the time of system bootup a status table in which a status indicating copy incomplete to for each physical block address of the nonvolatile memory unit, and a program which implements a memory access sequence of, when write access occurs from the OS or the application program to the nonvolatile memory unit during system operation and a status set in the status table indicates copy incomplete, copying data in a write destination physical block from the nonvolatile memory unit to an alternative block reserved in advance in the main memory unit only when a readable/writable attribute is determined upon referring to a protection information unit holding an intrinsic protection attribute of an access destination physical block, accessing the alterative block with a physical address obtained by changing a block address of a physical address for the write access into a block address of the alternative block upon updating a status in the mapping table to indicate that copying of the access destination physical block is complete, and when write access occurs from the OS or the application program to the nonvolatile memory unit during system operation and a status set in the status table indicates copy complete, accessing the alternative block with a physical address obtained by changing a block address of a physical address for the write access into a block address of the alternative block.

23. A medium according to claim 21 , wherein the main memory device comprises a plurality of nonvolatile memory units including the nonvolatile memory unit, which store different main storage bootup-memory-images of after initialization processing of the OS and the application program, the bootup program comprises a program which implements a sequence of causing the data processing apparatus to select one of the plurality of nonvolatile memory units at the time of system bootup, and the program which implements the mapping table initialization sequence comprises a program which implements a sequence of creating at the time of system bootup a mapping table in which mapping information of physical block addresses of the selected nonvolatile memory unit and a read only pseudo protection mode for logical block addresses of the system are set.

24. A medium according to claim 21 , wherein the program which implements the mapping table initialization sequence comprises a program which implements a sequence of re mapping at the time of system bootup a physical block address mapped to an area corresponding to a corrected image of the bootup-memory-image which is stored in the additional nonvolatile memory unit to a physical address mapped to the corrected image in the additional nonvolatile memory unit.